"_Second Experiment._--The patient sat with his back to the light, and kept his eye closed. A sheet of paper on which two strong black lines had been drawn, the one horizontal, the other vertical, was placed before him, at the distance of about three feet. He was now allowed to open the eye, and after attentive examination he called the lines by their right denominations. When I asked him to point out with his finger the horizontal line, he moved his hand slowly, as if feeling, and pointed to the vertical; but after a short time, observing his error, he corrected himself. The outline in black of a square [six inches in diameter], within which a circle had been drawn, and within the latter a triangle, was, after careful examination, recognized and correctly described by him. When he was asked to point out either of the figures, he never moved his hand directly and decidedly, but always as if feeling, and with the greatest caution; he pointed them out, however, correctly. A zigzag and a spiral line, both drawn on a sheet of paper, he observed to be different, but could not describe them otherwise than by imitating their forms with his finger in the air. He said he had no idea of those figures. "_Third Experiment._--The windows of the room were darkened, with the exception of one, toward which the patient, closing his eye, turned his back. At the distance of three feet, and on a level with the eye, a solid _cube_ and a _sphere_, each of four inches diameter, were placed before him. I now let him open his eye. After attentively examining these bodies, he said he saw a _quadrangular_ and a _circular_ figure, and after some consideration he pronounced the one a _square_ and the other a _disk_. His eye being then closed, the cube was taken away, and a disk of equal size substituted and placed next to the sphere. On again opening his eye he observed no difference in these objects, but regarded them both as disks. The solid cube was now placed in a somewhat oblique position before the eye, and close beside it a figure cut out of pasteboard, representing a plane outline prospect of the cube when in this position. Both objects he took to be something like flat quadrates. A pyramid, placed before him with one of its sides toward his eye, he saw as a plane triangle. This object was now turned a little, so as to present two of its sides to view, but rather more of one side than of the other; after considering and examining it for a long time, he said that this was a very extraordinary figure; it was neither a triangle, nor a quadrangle, nor a circle; he had no idea of it, and could not describe it. 'In fact,' said he, 'I must give it up.' On the conclusion of these experiments I asked him to describe the sensations the objects had produced,